When tobacco goods are smoked, two streams of smoke are produced. Main-stream smoke (MSS) is the smoke stream formed during the draw; side-stream smoke (SSS) is the smoke stream generated at the burning point of the tobacco in the interval between draws. Details and other definitions are contained in DIN/ISO 4387 and the paper by Neurath and Ehmke: "Apparatur zur Untersuchung des Nebenstromrauches", published in "Beitrage zur Tabakforschung 2"(1964) 117-121, to which reference is made here.
The odor of cigarette smoke is generally considered to be unpleasant by non-tobacco users. However, smoke overlaid or over-aged by side-stream smoke, known as "cold" smoke, is unusually objectionable to smokers and non-smokers alike. Non-smokers find several properties of this cold smoke to be particularly repellent. These objectionable properties include both the smell of the cold smoke, essentially, a "stale, bad odor" and irritation to the eyes and nose of particularly sensitive individuals.
Various attempts have been made to counteract these unpleasant nuisances, mainly via additives. These additives have the effect of simultaneously changing the taste of the main-stream smoke while affecting nuisance odors. The effect of the additives on the taste of the main-stream smoke represents a disadvantage in the form of limited freedom in cigarette design. A typical example of this is given in U.S. Pat No. 4,638,816, in which the additives added to the tobacco alter both the tobacco taste of the main-stream smoke and the odor of the side-stream smoke toward vanilla in each case; another example is EP-A 0 294 972, according to which similar effects are to be achieved by means of additives incorporated into the cigarette paper.
It is also known in the art, from DE-AS 1 771 622, that microcapsules containing flavorings or fragrances may be applied to the cigarette paper. The known microcapsules have a diameter of 5 to 100 .mu.m and are expediently placed on the side of the paper facing the tobacco. Disadvantages associated with this method include the form in which the microcapsules are applied, leading to a reduction in the porosity of the cigarette paper, and the size of the capsules, which can exceed the thickness of usual cigarette papers by up to three times. From the outset, size and arrangement of the capsules impede convenient processing of this type of cigarette papers because the capsules are prematurely destroyed by fast-running manufacturing machines. Cigarettes produced from cigarette papers supplied with microcapsules also have a tendency to form undesired spots and condensate stripes when the cigarette is smoked. In addition, the flavours used overlay or alter the original cigarette taste or smell with a certain odor or taste.
A need persists for a cigarette and cigarette tube, and analogously a tobacco cartridge and tobacco cartridge covering, with increased side-stream smoke acceptance while avoiding the disadvantages of the known processes, i.e. the side-stream smoke forming from this cigarette should develop a scent which, even after a prolonged time, is pleasantly tobacco-like, but as inconspicuous and weak as possible, free from irritant factors, and in no case substantially alters the taste of the main-stream smoke. At the same time, a convenient method of processing the tobacco strand or rod coverings, and a usual burn behavior of this cigarette, are provided.